US2011/0018737 (Hsu et al.) discloses a vehicle collision avoidance system implemented in a host vehicle. A wireless communication module in the host vehicle wirelessly broadcasts vehicle information packages of the host vehicle and receives external vehicle information packages from other neighboring vehicles. Based on the received vehicle information packages, a collision avoidance process is performed. The process has steps of mapping coordinates system, categorizing collision zones, determining whether a possible collision position exists, calculating a collision time and outputting warning messages.
US2002/0135467 (Koike) discloses that predicted future positions are calculated and arranged into packets to be transmitted using a communication pattern based on a time and a position of each packet. Another vehicle calculates its predicted position and generates a communication pattern based on a result of calculation so that the generated communication pattern is utilized for reception. Consequently, data associated with a future position of its own can be selected for enabling reception. An existence probability is calculated, and the state of another vehicle can be understood from the communication of the calculated existence probability, thereby reducing chance of collision. FIG. 20 in US2002/0135467 shows position coordinates of a user's vehicle and another vehicle from present to a few seconds later, wherein a portion where the trajectory of the user's vehicle overlaps on that of the another vehicle is a portion which a collision can be expected in the future.
However, US2011/0018737 and US2002/0135467 both calculate collision probability assuming both host (vehicle) and object (e.g. neighboring vehicle) motions are known.